In a surprise decision, Zaslav plans to move the merged cable giants from locations in Maryland and Manhattan to 230 Park Ave. South at 19th Street, The Post has learned.

Earlier reports said Discovery, which plans to sell its headquarters in Silver Springs, Md., had narrowed its Big Apple short list to two other Manhattan addresses, 441 Ninth Ave. in the Hudson Yards district and 1250 Broadway in Koreatown.

Instead, sources said, the company’s chief executive plans to consolidate both Discovery’s and Scripps’ employees into about 250,000 square feet at the building just north of Union Square.

The TF Cornerstone-owned building dates to 1895 but boasts state-of-the art HVAC, mechanical and fiber-optic systems.

Zaslav spent Wednesday morning at Food Network’s studio there before giving an interview to CNN, saying the newly merged company will be “the leader in real-life entertainment around the world.”

Discovery and TF Cornerstone have yet to sign a lease. But a source said, “while something crazy can always go wrong, it’s unlikely. Other tenants have already agreed to move out early.” Tenants include divisions of WPP Group.

Discovery currently leases about 160,000 square feet at 850 Third Ave. and owns a 550,000-square-foot building in Silver Springs. It was not known how much of the Maryland property Discovery actually uses.

Discovery plans to move to its new digs next year, sources said. It wasn’t known how much if any space it will keep at the other three Manhattan addresses.

Asking rents were said to be in the high $70s to low $80s per-square-foot range.

“It’s in the same ballpark as at the other buildings they looked at,” an insider said. “The decision wasn’t about rent — they just really wanted to be on Park Avenue South which is teeming with creative and entertainment companies.”